Relining effects on the push-out shear bond strength of glass fiber posts

Efeitos do reembasamento sobre a resistência ao cisalhamento por extrusão (push-out) de pinos de fibra de vidro

Abstract

Introduction

The correct use of glass fiber posts in endodontically treated teeth is essential for the clinical success of restorative treatment.

Objective

This study evaluated the push-out shear bond strength of relined (R) or non-relined (NR) glass fiber posts, cemented with self-adhesive resin cement [RelyX^TM U100 (U100)] and conventional resin cement [RelyX^TM ARC (ARC)].

Material and method

Sixty human single-rooted teeth were endodontically treated and divided into ARC-NR; U100-NR; ARC-R; U100-R groups. The teeth were sectioned into cervical, middle and apical thirds, and subjected to the push-out test. Bond strength was analyzed by the Friedman test; cement and post types were compared by the Mann Whitney test. The pattern of failures was evaluated with digital camera through images at 200x magnification, and was classified as adhesive (at the cement/dentin or cement/post interface), cohesive (cement or post), and mixed failures.

Result

In ARC-NR, bond strength values were higher in the cervical third; in U100-NR and ARC-R they were similar between the thirds. In U100-R, in the cervical and middle thirds the bond strength values were similar, and there was lower value in the apical third. For non-relined glass fiber posts, the highest mean bond strength values were observed with self-adhesive resin cement. Whereas, relined posts cemented with conventional resin cement had stronger cement layer in comparison with non-relined fiber posts.

Conclusion

The post relining technique was efficient in ARC-R. ARC-NR and U100-R showed improved bond strength in the cervical region of canal walls. The main failures were adhesive at the cement-post interface.

Descriptors:
Dental bonding; dental materials; dentin; post and core technique; shear strength